I do two schools, both outsides only which is perfect,
Smaller one takes 3 hours - £135.00
Bigger one takes 5 hours and is £280.00 (I thought it would take up to 8 hours when quoting, give yourself leeway)
Both are cleaned twice a year, the first one is an academy, the second is a school for special needs/learning difficulties.
When quoting I just used experience and kind of ‘knew’ roughly how long they’d take.
I’m always suprised how quickly you can bosh them out, just take a look at the state of the windows, and then work out how long you think it’ll take, add on a bit just in case.